The influence of maternal and paternal components and breeding season on the reproductive results of New Zealand White and Californian female rabbits

Abstract

The research compares reproduction of female New Zealand White (NZW, n=55) and Californian (CAL, n=12) rabbits after mating with pure-bred Flemish Giant, Californian, and Burgundy Fawn males, as well as New Zealand White and Californian crossbred males. The influence of the dam’s breed, the birth season, and the parental component on reproduction parameters was analysed. Three groups of does were studied: those which had two litters (21 females), those which had three litters (15), and all does (irrespective of the number of litters, i.e. 67 females). In the first group, the mother’s breed was found to affect litter size at weaning (5.20 for Californian and 7.33 for New Zealand White), which was largest for the NZW×CAL crossbreed (10.50). Among the females with three litters, the breed of the dam influenced rearing efficiency, with greater efficiency noted for the New Zealand White breed (90.2%) than for the Californian breed (69.8%). Where all litters were considered, the two breeds differed in terms of the number of live-born kittens per litter (6.59 for NZW vs 7.71 for CAL) and litter size at weaning (6.34 vs 7.50). In this group, litter size at weaning was larger in winter (4.65) than in autumn (2.00). New Zealand White females that mated with Flemish Giant males produced fewer live-born kittens per litter (5.85) than Californian females that mated with Burgundy Fawn males (10.00). Pure-bred litters were smaller (2.04) at weaning than crossbred ones (from 5.39 to 10.00). For females with three litters, repeatability was 0.36 for total litter size and 0.35 for the number of live-born kittens per litter. For litter size at weaning, however, it was only 0.15, indicating a strong effect of environmental factors on rearing outcomes.

Genetic parameters of growth traits and carcass weight of New Zealand white rabbits in a tropical dry forest area

“…The result of BA and DB were similar to those reported in the literature for the same breed by Pycha et al [ 15 ], although Pollesel et al [ 16 ] have reported values higher than those found in this study. It has been reported that animals with higher birth weights have higher body weight at the first service and during their entire productive cycle [ 17 ].…”

“…r for traits LB, BA, LW, LWS, and SW presented a low magnitude, indicating a strong influence of environmental factors. Similar results for various litter-related traits were presented by Pycha et al [ 15 ], Behiry et al [ 30 ], and Karim et al [ 41 ]. For the WW and CW traits, the values obtained from r tend to be moderate; similar reports were presented previously [ 3 , 9 ].…”

“…The mean LB value obtained here was higher than that presented by Gambo et al [ 4 ] and Adeolu et al [ 8 ], but lower than the reports by Badawy et al [ 14 ] and Pycha et al [ 15 ]. The differences found between the different reports for BL may be due to the disparity in the conception rate and the maternal effect, which is generally determined by the number of eggs matured, fertilized, and implanted by the doe [ 8 ].…”

“…A measure of the similarity of the performance of individuals in successive litters throughout the yield cycle is repeatability. It depends on both genotypes and environmental factors [ 15 ]. Estimates of r for the evaluated traits ranged between 0.12 and 0.42 ( Table 2 ).…”